Teacher education is not in good philosophical health. This chapter will address the situation of pre-service and postgraduate students in science education. There are many reasons why the history and philosophy of science (HPS) should be part of pre-service and in-service science teacher education programmes. Increasingly school science courses address historical, philosophical, ethical, and cultural issues occasioned by science. Beyond these ‘practical’ arguments for HPS in teacher education, there are compelling ‘professional’ arguments. A teacher with pride in their profession must understand the body of knowledge they are teaching, how this knowledge has come about, how its claims are justified, what its limitations are, and, importantly, what the strengths and contributions of science have been to the betterment of human life. Overall, HPS allows science teachers and science education researchers to better understand their own social and professional responsibilities as part of a great Enlightenment-based knowledge-seeking and society-improving tradition. In this context, a case study of Constructivism in the theory and practice of science education will be elaborated here. Additionally, science teachers as with all teachers need to be engaged with the core questions addressed in philosophy of education: aims of education; breadth of knowledge; identification of indoctrination and its acceptable and unacceptable usage; appropriate and inappropriate roles of parents, the state and church in education decision-making; bounds on disciplinary measures; equality of opportunity; use of competitive national and provincial testing; and so on. The latter, generic philosophical matters, are discussed in other contributions to this anthology; they are not taken up here.